Jump to content
Sign in to follow this  

Just bought a 2006 450x have some questions

Recommended Posts

So I just bought a 2006 450x and am getting ready to tear into it. The previous owner just put a r cam in it, trx valves, and fresh piston and rings. The bike starts and runs with the choke on but as soon as the choke is off it quickly dies. I just got the FMF powercore4 with powerbomb header, PC flow air filter, new spark plug, and plan to install them this weekend. I will also change oils and do the airbox mod as well. Most of my reading here tells me to rejet to 48 pilot, 165 main, needle 3rd from top, and fuel screw out 1 3/4 turns. 1st question, what are the stock size jets can I modify mine by drilling them out and is this info correct for my configuration? 2nd question, I am looking at my sons old race bike ( 2005 CRF 250R ) and wondering if there is anything I could swap over to the 450X? I know some of the bolts ons will but what about the suspension, forks, shock, triple clamps? The suspension was done by Pro Prept and only has 3 races on it. I am not to concerned about having to modify anything or make something to make it work, I have access to a machine shop. Just want to know if it can be done before I tear 2 bikes apart. Last question, has anyone done the trx valve mod and can you tell me a little about it, pros-cons, and is the clearance different. Thanks, any info will be appreciated.

Share this post


Link to post
Share on other sites

First, your pilot jet is clogged.

Second, the suggested jetting is a good place to start. With the cost of new jets so low, it' doesn't make sense to drill out old ones. Original jetting 142 main, 45 pilot. I would also bump the leak down to a 50. The needle should be swapped with an NCVS.

Third, triples and forks will swap over, however unless you weigh less than 140 lbs, you will need new springs to account for the added weight of the X over a 250R. Shock will physically fit, however it will change the geometry and be hard to tune.

The TRX valve mod uses the steel valves from the TRX450R quad. The life span of the steel valves will be much greater than the Titanium units. Some will say that you will lose power. That's BS. Nobody can tell the difference. The clearances can be the same as stock, or a lighter tighter for added performance and life.

Share this post


Link to post
Share on other sites

Thanks for the info, can you eloborate on the shock issue just cause I'm curious. I will probably swap the suspension with my wifes 250x anyways. Going head to ECC today and get all the parts to do the jetting, will report back Monday morning with results. Thanks again.

Share this post


Link to post
Share on other sites

The lower portion of the shock, known as the clevis, is a different length in regards to the mounting hole. This will change the geometry of the bike and cause it put more weight on the rear of the bike losing it's balance. It will also cause the shock to sit in a different part of the stroke causing a more harsh ride characteristic.

The valving for a 250 will be less stiff and the added weight of the 450 will cause the shock to blow through it's stroke. The springs for the 250 are a 4.8kg/mm whereas the 450 is a 5.5kg/mm.

Why do you need to swap suspensions?

Share this post


Link to post
Share on other sites

Hi my name is duane and I just recently picked up a 06 450x. I know you probably get this a lot and I have already done a lot of research on the subject. So here it goes. As far as right now this is what's done to the bike, it has a fmf ti powercore slip on, no smog from factory, no air box mods but did remove backfire screen, just cut the ap diaphram rivet and installed o-ring, went from a #142 main to #162, #42 pj to a #45 and then now to a #48, 2 1/4- 2 1/2 on air/fuel, no decel pop, I don't have a fuel screw so hard to really tell where I need to be but with the #42 pj at 2 1/2 turns I had decel pop, nothing at 3 turns out so tried a #48 pj, just don't know if #48 is to much, it has the ncvu needle on 5 clip from top, leak jet still #70. Don't really have any issues with bog but I know it could be even better my question is well today was like 76 77 and the idle just seems weired, it's either to low or seems to high, I'm at sea level and live in lake havasu city, az and it gets hot here. Is #48pj to much, should I open up the airbox, change the needle to a ncvs, change the leak jet to a #65 or block it off and is the 162 main good, appricate any help, thanks duane oh and what should I get for a air/fuel screw and if it's the r&d one how do you know how many times your turning it out

Share this post


Link to post
Share on other sites

You've got to open the air box; at least remove the snorkel.

Stange idle is probably a destroyed o-ring on the stock fuel screw, or a destroyed slide plate seal. Replace them.

All fuel screws are mark with a logo or markings.

Share this post


Link to post
Share on other sites

Why do you need to swap suspensions?

The main reason would be that I have around $800 in suspension on a bike that sits in the corner.

Also the forks on the 450x are pretty beat up, extremely pitted and have a few chunks taken out.

Share this post


Link to post
Share on other sites

I forgot to mention, that I well I ride my bike to work everyday and was tring to figure out how many mpg I was getting, ran bike down to reserve, stopped and put a gallon of 91 in and then a gatorade bottle full of av gas 100 octang and that when the idle started to sound funny, am I just to rich and not enough air comming through the airbox, going to mess with the fuel screw today and see what that does and maybe even go back to a 45pj instead of 48pj

Share this post


Link to post
Share on other sites

Do not use AV gas 110LL or 100LL in your bike. The higher the octane, the slower the burn rate, or flame spread index. The bike will run on regular gas just fine and will make more power. Just wasting money and performance.

Share this post


Link to post
Share on other sites

Why do you need to swap suspensions?

The main reason would be that I have around $800 in suspension on a bike that sits in the corner.

Also the forks on the 450x are pretty beat up, extremely pitted and have a few chunks taken out.

The forks are OK to swap, but you'll want to respring for your weight and possibly revalve to get the best performance.

Share this post


Link to post
Share on other sites

Congrats on the new bike. CRF Doc has a lot of good suggestions. As far as the suspension have you considered selling your sons bike that is just sitting around and using the money for tuning up your suspension. Not sure what you weigh but the correct springs,fresh oil and the correct sag goes a long way. Dblanchard450x mentioned something about a #48 pilot jet. I have smog blocked,air box cut,full exhaust system,#170 main jet,#48pilot jet,#55 leak jet,JD Red needle 4th clip from top. I noticed my bike seemed to be running a little rich and idling strange. Wanted to stall when on slow tight single track type terrain with clutch pulled in. Slide plate in carb is fairly new and also new fuel screw O ring. I was going to try and go back to stock pilot jet #45 and raise the needle clip to third position. (lower the needle) I hope it works we'll see ? I wonder if that's why the JDJet kit doesn't come with a different pilot jet. I usually ride around sea level to 3,000 feet so elevation. shouldn't be an issue. I ride around Havasu alot of fun riding but that's a different topic. Anyway enjoy your new toy.

Share this post


Link to post
Share on other sites

Congrats on the new bike. CRF Doc has a lot of good suggestions. As far as the suspension have you considered selling your sons bike that is just sitting around and using the money for tuning up your suspension. Not sure what you weigh but the correct springs,fresh oil and the correct sag goes a long way. Dblanchard450x mentioned something about a #48 pilot jet. I have smog blocked,air box cut,full exhaust system,#170 main jet,#48pilot jet,#55 leak jet,JD Red needle 4th clip from top. I noticed my bike seemed to be running a little rich and idling strange. Wanted to stall when on slow tight single track type terrain with clutch pulled in. Slide plate in carb is fairly new and also new fuel screw O ring. I was going to try and go back to stock pilot jet #45 and raise the needle clip to third position. (lower the needle) I hope it works we'll see ? I wonder if that's why the JDJet kit doesn't come with a different pilot jet. I usually ride around sea level to 3,000 feet so elevation. shouldn't be an issue. I ride around Havasu alot of fun riding but that's a different topic. Anyway enjoy your new toy.

Got the bike in 2005 from someone who bought it for his wife but she had a hard time riding it cause it was too tall for her. I never registared it cause we were only gunna race it so it has not been stickered since 2007 and I don't have the pink slip for it. The previous owner used the money I gave him to pay off the loan but lost the pink slip after the bank sent it to him. After a couple of races and thousands later in suspension, engine work, and expensive bolt-ons my son quit riding. Held on to the bike hoping he might want to race again. Difficult to sell a bike that hasn't been registared in years and you don't have the title for. Just got a 250x for the wife so I will probably switch over what I can onto that bike and part out the rest.

Share this post


Link to post
Share on other sites

450xsurfur where are from? I live in lake havasu city and love the riding here. Crf doc, I don't run straight av gas I mix it half/half with 91 octang and as far as I have always been taught, a bike will run fine of race gas as long as it is jetted right for it but hey maybe I was taught wrong. Well anyway, I messed with my bike today and I think I figured it out as far as the weired idle. I had the air/fuel turned out to far, with a #48pj I was at 2 1/2 turns out, now I have it set at 1 1/2 and it seems to be fine now and also turned the idle up a bit and that's with av gas in it, runs fine. I noticed with av gas that I run in all my bikes, it seems to give a more crisp throttle response but hey that's me. Anyway going to probably open up the top of airbox this weekend and I have a r&d flex jet on it's way.

Share this post


Link to post
Share on other sites

Do not use AV gas 110LL or 100LL in your bike. The higher the octane, the slower the burn rate, or flame spread index. The bike will run on regular gas just fine and will make more power. Just wasting money and performance.

In Aus, I have been running my crf on premium (98 octane) unleaded. Should I not bother

Edited by MrNoodle

Share this post


Link to post
Share on other sites

MXDad, I have an '05 with open airbox, stock exhaust and a Hotcam stage 2 cam. Similar to your setup. I went with the jetting suggested here which is a 162 main, 48 pilot and a 50 leak, needle clip on the fourth. Runs great and starts easy. Be sure to clean out the pilot and accelerator pump passages when you clean and rejet, They cause misery when clogged. Adjust your valve lash same as stock except the decompression. Adjust the decompression in until it turns over easy and your good.

Share this post


Link to post
Share on other sites

Hey I found a 08 450r cam for $40 for my 450x, should I get it and do I have to do anything special to other parts of the bike if I want to install just the cam?

Share this post


Link to post
Share on other sites

Hey I found a 08 450r cam for $40 for my 450x, should I get it and do I have to do anything special to other parts of the bike if I want to install just the cam?

won't work. 2005 and earlier only, unless your X is newer.

Share this post


Link to post
Share on other sites

Finally got a chance to work on the bike since my last post and as soon as I removed the float bowl drain screw the pilot jet fell out. It must of vibrated loose. The threads looked a little worn out. I put in a new # 48 pilot and a little cleaning. Set the fuel screw at two turns out and fired it up. Runs perfect. I think I'll stick with the # 48 pilot. Dblanchard to answer your question I live in Huntington Beach.

Share this post


Link to post
Share on other sites

450xsurfer, when do u ride in havasu? Maybe when your out here we could ride together. If you want to get ahold of me pm me and I'll give u my #

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...